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Biomedical subjects

K Ryan-Poirier

Publications and source records attributed to K Ryan-Poirier.

6 recordsLinked to original sources
PubMed1998

Changes in H3 influenza A virus receptor specificity during replication in humans.

Influenza A viruses of the H3 subtype caused the 1968 Hong Kong pandemic, the hemagglutinin (HA) gene being introduced into humans following a reassortment event with an avian virus. Receptor specificity and serum inhibitor sensitivity of the HA of influenza A viruses are linked to the host species. Human H3 viruses preferentially recognize N-acetyl sialic acid linked to galactose by alpha2,6 linkages (Neu5Acalpha2,6Gal) and are sensitive to serum inhibitors, whereas avian and equine viruses preferentially recognize Neu5Acalpha2,3Gal linkages and are resistant to serum inhibitors. We have examined the receptor specificity and serum inhibitor sensitivity of H3 human influenza A viruses from the time they were introduced into the human population to gain insight into the mechanism of viral molecular evolution and host tropism. All of the viruses were sensitive to neutralization and hemagglutination inhibition by horse serum. Early H3 viruses were resistant to pig and rabbit serum inhibitors. Viruses isolated after 1977 were uniformly sensitive to inhibition by pig and rabbit sera. The recognition of Neu5Acalpha2,3Gal or Neu5Acalpha2,6Gal linkages was not correlated with the serum sensitivity. These data showed that the receptor specificity of HA, measured as inhibitor sensitivity, has changed during replication in humans since its introduction from an avian virus.

Amino Acid Sequence↗
PubMed1993

Cervical adenitis caused by Staphylococcus epidermidis.

Staphylococcus epidermidis, a human commensal, is a common cause of bacteremia in immunocompromised patients with indwelling medical devices. We report a case of isolated cervical adenitis caused by S. epidermidis in an immunocompetent patient and comment on the presumed pathogenesis.

Anti-Bacterial Agents↗
PubMed1992

Comparison of different approaches to measuring influenza A virus-specific hemagglutination inhibition antibodies in the presence of serum inhibitors.

The A/Los Angeles/2/87 (H3N2) (A/LA/2/87) virus is sensitive to inhibitors of hemagglutination present in certain human sera. It was found that the effect of these inhibitors could be removed by treating sera with high-concentration receptor-destroying enzyme or trypsin-periodate or by using inhibitor-resistant viruses in the hemagglutination inhibition (HAI) test. Inhibitor-resistant viruses were not effective for detecting rises in antibody titers in the sera of volunteers infected with the A/LA/2/87 wild-type virus, while rises in antibody titer were readily detected in sera treated with trypsin-periodate and tested against A/LA/2/87 wild-type virus in an HAI test. It is therefore suggested that chemical or enzymatic methods be used to inactivate serum inhibitors and that standard virus be used in the HAI test for the currently circulating H3N2 viruses.

Antibodies, Viral↗
PubMed1988

Post-traumatic cutaneous mucormycosis in diabetes mellitus. Short-term antifungal therapy.

Mucormycosis is infrequently encountered in the pediatric population in any of its forms (nasopharyngeal, disseminated, pulmonary, or cutaneous) and generally is associated with the immunocompromised host. We present an adolescent with poorly controlled diabetes mellitus who developed a progressive skin lesion 3 weeks after a motor vehicle accident. Rhizopus species was isolated from the lesion, and the biopsy revealed a fungal vasculopathy. Control of her diabetes, aggressive surgical intervention and a 10-day course of antifungal therapy (amphotericin B) resulted in a favorable outcome. This article illustrates the importance of considering cutaneous fungal infections, especially those in the class zygomycetes, in the diabetic patient with unusual, severe or persistent skin lesions. Early recognition is essential in order to avoid morbidity and mortality from this unusual opportunistic infection.

Accidents, Traffic↗